The term 'BACK WITH BUCKS' can be broken down into two crossword solutions: BETON (5 letters) and BANKROLL (8 letters). BETON is a type of concrete made from cement, sand, and gravel. It is often used in construction projects due to its strength and durability. BANKROLL is a term used to describe a large sum of money that is available for use. It is often used to refer to the money that someone has saved or invested.